Pyrans and their Benzo Derivatives: Synthesis

Brimble, Margaret A.; Sperry, Jonathan; Gibson, Justine S.

doi:10.1016/b978-008044992-0.00608-8

Cited by 24 publications

(12 citation statements)

References 1,435 publications

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“… 2 This method and other similar methods have drawbacks including abundant side reactions, low yields, and difficulty in separation. 19 − 21 Friedel–Crafts acylation of suitably substituted benzoyl chlorides with alkynes was reported for chromone and flavone synthesis, 22 , 23 but this method is associated with the use of large quantities of hazardous soluble Lewis acids (e.g., AlCl 3 , FeCl 3 , and TiCl 4 ), which made this method as one of the most challenges for green chemistry. 24 , 25 Copper(II)-catalyzed cyclization of 1-(2-hydroxyaryl)-3-aryl-1,3-propanedione under microwave irradiation was reported for the synthesis of functionalized flavones and chromones.…”

Section: Introductionmentioning

confidence: 99%

Regioselective Synthesis of Chromones via Cyclocarbonylative Sonogashira Coupling Catalyzed by Highly Active Bridged-Bis(N-Heterocyclic Carbene)Palladium(II) Complexes

2020

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The one-pot regioselective and catalytic synthesis of bioactive chromones and flavones was achieved via phosphine-free cyclocarbonylative Sonogashira coupling reactions of 2-iodophenols with aryl alkynes, alkyl alkynes, and dialkynes. The reactions are catalyzed by new dibromidobis(NHC)palladium(II) complexes. The new bridged N , N ′-substituted benzimidazolium salts ( L1 , L2 , and L3 ) and their palladium complexes C1 , C2 , and C3 were designed, prepared, and fully characterized using different physical and spectroscopic techniques. The molecular structures of complexes C1 and C3 were determined by single-crystal X-ray diffraction analysis. They showed a distorted square planar geometry, where the Pd(II) ion is bonded to the carbon atoms of two cis NHC carbene ligands and two cis bromido anions. These complexes displayed a high catalytic activity in cyclocarbonylative Sonogashira coupling reactions with low catalyst loadings. The regioselectivity of these reactions was controlled by using diethylamine as the base and DMF as the solvent.

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Section: Introductionmentioning

confidence: 99%

Regioselective Synthesis of Chromones via Cyclocarbonylative Sonogashira Coupling Catalyzed by Highly Active Bridged-Bis(N-Heterocyclic Carbene)Palladium(II) Complexes

2020

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“…[23,24] Construction of novel indolyl derivatives, incorporating a 2H-chromene ring at the C3 position of indole, is a great value. [25][26][27] From the literature reports, synthesis of indole incorporated chromene derivates was carried out by using Lewis acids or bases. [28,29] However, these methods were suppressed by the usage of metal catalysts and hazardous, expensive organic solvents.…”

Section: Introductionmentioning

confidence: 99%

Water Extract of Lemon (WEL) as a Promoter: Green and Regioselective Synthesis of Alkyl‐4‐(1H‐indol‐3 yl)‐2‐alkyl‐4H‐chromene‐3‐carboxylates Using 4H‐chromenes and Indoles

Vasantha

Lenin

Rao³

et al. 2020

ChemistrySelect

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An efficient, simple, green, regioselective and catalyst-free synthesis of alkyl-4-(1H-indol-3yl)-2-alkyl-4H-chromene-3-carboxylates is disclosed by employing indoles and substituted chromene derivatives under mild reaction condition. This is a novel green methodology, simple, eco-friendly and easy to operate. Biomass-derived catalyst Water Extract of Lemon (WEL) was used as a promoter for this procedure. The methodology could be applicable for cost-effective large scale production of alkyl-4-(1H-indol-3yl)-2-alkyl-4H-chromene-3-carboxylates in good to excellent yield.

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“…Heterocyclic compounds represent a large family of organic compounds (Katritzky et al, 2010;Brimble et al, 2008), they are known for widespread applications in various ields because of their biological importance, medicinal chemistry, and chemical biology. The 2H-chromene (2H-1-benzopyran) moiety is one of the most important heterocycles detected in many biologically active natural products and in synthetic compounds (Kolokythas et al, 2007;P et al, 2009;Schweizer and Meeder, 1977) 2H-chromenes were reported to display signi icant antioxidant (Kwak et al, 2006) , antiviral (Martínez-Grau and Marco, 1997) , antimicrobial (Li et al, 2018) anti-in lammatory (Gebhardt et al, 2007) and antifungal (Chanu et al, 2017) properties, in addition to their interesting applications as highly effective luorescent dyes (Moorthy et al, 2006) Furthermore, several metal complexes of chromene derivatives possess antimicrobial (Soliman et al, 2016) DNA cleavage activities (Prabhakara et al, 2015) and photoluminescence properties (Aazam et al, 2012) .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, Antimicrobial, DNA Cleavage and Fluorescent Activity of Metal ion(II) Coordinate with 2H-Chromene Azo novel ligand

Nafea¹,

Kawaz²

2020

ijrps

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A new ligand 2H-chromene containing azo group 2-(4-nitrophenyl)-N-(4-(phenyldiazenyl)-2H-chromen-4-amine (AH), were synthesized from the condensation reaction (1:2)of 2'-hydroxychalcone and p-aminoazobenzene. Co(II), Cu(II) and Ni(II) complexes of the new ligand have been synthesized and characterized using C.H.N. analysis,1HNMR spectra, FT.IR, UV/Visible, magnetic susceptible, conductance measuring, and fluorescence spectral spectroscopy; 13CNMR spectroscopy of the ligand was also studied. Spectroscopic results revealed the 2H-Chromene Azo (AH) ligand behaves as monodentate chelating via the nitrogen atom of amine groupat position 4 having 1:1 [M:L] ratio; suggested that the cobalt and nickel complexes have the tetrahedralstructure and a distorted tetrahedralgeometry for the copper complex, indicating their non-electrolyte nature. The new ligand shows a fluorescence emissioncomparingwith this fluorescence quenching was noticed in its metal complexes. The antibacterial potency of the free ligand and its chelates with metal ion(II) were screened against E.coli, K.pneumoniae, Staph.aureus andB.Subtilis;The DNA cleavage activity of the free ligand and its 2H-chromene azo metal (II) complexes was performedby the gel electrophoresis process, which giventhat thesecompounds are effectiveupon DNA cleavage .

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Pyrans and their Benzo Derivatives: Synthesis

Cited by 24 publications

References 1,435 publications

Regioselective Synthesis of Chromones via Cyclocarbonylative Sonogashira Coupling Catalyzed by Highly Active Bridged-Bis(N-Heterocyclic Carbene)Palladium(II) Complexes

Regioselective Synthesis of Chromones via Cyclocarbonylative Sonogashira Coupling Catalyzed by Highly Active Bridged-Bis(N-Heterocyclic Carbene)Palladium(II) Complexes

Water Extract of Lemon (WEL) as a Promoter: Green and Regioselective Synthesis of Alkyl‐4‐(1H‐indol‐3 yl)‐2‐alkyl‐4H‐chromene‐3‐carboxylates Using 4H‐chromenes and Indoles

Synthesis, Characterization, Antimicrobial, DNA Cleavage and Fluorescent Activity of Metal ion(II) Coordinate with 2H-Chromene Azo novel ligand

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